Butterfly at outlet of PSV
Butterfly at outlet of PSV
(OP)
We have an installation with a butterfly valve (isolating valve) at the outlet of a psv. We usually put gate valve with CSO. Is the used of that kind of valve allowed with APi *(Is this consider a block valve). My application is for light naphta.
Thanks,





RE: Butterfly at outlet of PSV
RE: Butterfly at outlet of PSV
my application is a 4'', 150# butterfly valve with TFE seat.
Will the teflon seat wear as the metal seat ?
Regards,
RE: Butterfly at outlet of PSV
Whether you consider a butterfly valve adequate enough for isolation is one issue.
What may be a more important concern is whether you can ensure that the valve disk does not somehow become disconnected from the valve operator and block the flow.
API RP-520 Part II specifically notes...
"When gate valves are used, they should be installed with stems oriented horizontally or, if this is not feasible, the stem could be oriented downward to a maximum of 45' from the horizontal to keep the gate from falling off and blocking the flow."
It would seem you could have a similar concern with a butterfly valve but I don't think you could position the valve to address the concern the way you could with a gate valve.
RE: Butterfly at outlet of PSV